Light-splitting device for color photography.



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TE TDD/S DATE FILN CAMERA REEL OPERATOR LIGHT SPLITTING DEVICE FDR COLOR PHOTOGRAPHY.

APFLICAYIOI FILED PLL Hl. I

lIlI

Patented Aug. 27, 1918.

3 SHEETS-"WET 2.

#41:2 L///\0-/ 'Uv 1 |,fv-... l onf/Rn; EMPLOYEES No. DATE Ton/slome HLCAMERAI un. l OPERATOR P. D. BREWSTER. LIGHT SPLITTIG DEVICE FOR COLOR PHOIOGRAIHY.

Armcmon fluo strnz. un. 1,277,040 Patented Aug. 27, 19m

3 SHEE'l-SIIEET I.

'onto the censiti *Wbl v: DATUREC. EMPLOYEES N. UTE TOUS DATE FIL CAME RA REEL OP ERATOI UNITED STATES PATENT OFFICE t 'mor n. or'nasr enanas, isrrfw massif. sarasota To' v-= r .'I concurren; or'nwanx, xn'w a 'consonnes or trxw'o'ax.

mennen i man rims.

'Patenteli Aug. 27, 1918.

Application lied mantel-M1011. lex-talle. 118,1.

I higher thun wide) may be constructed in Toallwhomitmayconccrn:

Be it known that I, Pniicr D. Bnwsrnn, a citizen of tlic United States, residing at East Orange, in the count of Essex and State of New Jersey, have invented certain new and useful Improvements. in Lightf Splitting Devices for Color Photography, of which the following is-a full, clear, 'and exact description.

M present invention relates to'means of dividing the light rays projected by a lens into'two or more grou s for use primarily iii color photographyv or securing se arate simultaneous colei-records of the object to be hotograplied.

he object of my invention is, in general, to :provide a method of projecting absolute y even images without distortion on the entire plate, and t provide means for accurately and easily securing any plroportion of reflected and transmitted ig t, and for permitting easy cleaning.

In the drawin Fi re 1 is a horizontal section through t 1e sp itting mirror mount ed in a camera which is shown diagrammatically.- Fig. 2 is a vertical section of the' same. Fig. 3 is an elevation of the splitting mirror. l Fig. 4'is a plan view of the mirror and holder. Fig. 5 is a section through the filling device. Fig. 6 is a sectional plan view of a three color camera. Figs. 7 and 8 are n plan view and a vertical section, respectively, of-a modified type of cube.

Lens 1 and shutter 2 are mounted adjustubly on the camera box 3 and connected to it b' bellows 4. Light rays projected by the ens pass through the glass side 6 of the cube 5, the 4light rays passing through the liquid und striking the splittinmirror 7 mounted at an angle to the ight rays (shown as forty-five degrees). This mirror is coated on its front or rear surface with bands f silver o'r other highly rellective substance as shown in Fig. 3, the silver being in'strips. squares, rounds, or an other pattern. The light ra slstriking t e sil- -vered portions are re ected thro h the .liquid and glassv late 8 and color ter '9 emulsion 10 on 'the -plate or film. The light rays striking the clear or unsilvered ortions pass through the lassmirror 7, t eliquid,glass plates 11 and t e filter 12, and -act on the emulsion on .plate or Hlm 18.

The cube 5 (ao-called, though it usually is le .y mit@ cube is miei with aiiquid 1min; m

uny way desired-providing three of its sides are made of glass or other highl transpar- 'cnt'materiaL It is n'ot essentia that' it be shaped as a cube or even that the glass platea be the same distance from thel tersection ofthe axial ray and e reecting surface of the mirror. As illustrated, it consists of 'a cube with three int of insides opg Two of these sides are covered by the g latesS and 11 held in lace by the rim an 14 und 15z attac ed to the cube. Pac ing of any suitable material is placed between the riiu flange and the lass and between the rim flange and the cu totirevent the leakage of any of the liquid in* e cube. On the side of the cube toward the lens i a a flange 16, open at the center, and having .twoprojections 17, 17 (the ends of whic are finished to form the angle at which the 76 splitting mirroris to be mounted) which bv jmeans of lugs 18, 18 are arranged to hold the splittingl mirror in place. The inner side 19 of t e flange 16 is arranged to t' against thecube, while the other side 20 a0 (preferably parallel 'to face It? is adapted to receive thc glass plate hel in glace by lrim flange 21 and made tight by t e same 4form Iof packin The two-glass sides of4 the cube are'pre erably parallelto their nel5 spective plates (that is, the light-sensitive -plates which are to receivethe light raya) and at .right angles tp each other while the glass plate toward the lens is preferably parallel to the plate receiving the raya at which are transmitted through instead of reflected by the li hic-splitting mirror or mirrors. It is pre crab e (though not easential) that the optical 'path of the reflected and transmitted rays be the same to al -the outside of glaes 8 and 11.

A stub shaft 42 projects froin'the base of the cube 5 and is adapted 'to-a hole in the base 3 its center being directly below the point of 'intersection of the axial ray and l the splittingr surface of the mirror ao that Vrotating the cube will shift thaiimage evenly on the reflected plate and insure; of the mirror exactly to itLpnd index of refraction of about the lame aa lass used in the splitting mirror-ch iquids as l cerin, .castor oil, mineral oil, carbon bisu d, or 'glycerin and water eon I wel? I lll/- i DATB'REC.I ENPLQYEES NO. MTE TOD/S DATE FIL CAMERA OPERATOR taining a lead salt such as the nitrate' or acetate. The glass in plates 6, 8 and 11 should be free from struc or strain and be very nearly parallel en the two surfaces.

It is desirable to have a ve small amount of air or other gas in the cu to allow for expansion of the fluid due to heat and as the cameras are frequently turned on their sides it is advisable to have an air trap 22 such as is `shown in Fig. 5 used which is tap ed into the top of the cube (preferablyresigned with a conical top) and which consists of the coiled tube 25 in connection with the liquid in the cube. The cube is then filled through filler 23 until the liquid runs out of the coiled pipe 25 showing the cube and coil full of liquid and free from air, the filler 23 is then sealed by cap 24 and the cap 26 is put on the air trap, leaving the Space in the tra full of air. Expansion or contraction o the li uid in the cube can only change the level o the fiuid in the coil pigs and no air at any time can get into the cu ivhere it might badly interfere with the ima Iishe refractive index of the fluid be very near that of the glass used in the mirror the glass may be silvered on its rear face, as there will be no image retiected from its front surface.

The three-color camera shown in Fig. 6 is similar to the two-color except that the cube contains another mirror 31 adapted to be partly silvered and consequently refleet part of the light transmitted through the first mirror 7 and also transmit a portion. The transmitted light passes through the mirror 31, the liquid, the plate 11, and filter 29, onto emulsion 30; while the relected rays pass throu h glass filler 35, and act on ein sion 36. e mirror 31 is supported by the proections on the flan e 32 to which the glass p ate is secured by t e rim-flange 34.

The red filter may be placed at 27 and a red sensitive or panchromatic plate at 2.8 and the green filter at 35 and a sensitive or panchromatic plate at 36, while the transmitted light may ass through blue filter 29 and act on the b ue sensitive plate.

In the type of cube illustrated in Figa. 7

and 8 the mirror 7 maybe mounted in the cradle 37 which is provided on both ends with stub shafts or trunnions 38, 38, adapted to turn in holes bored out in the top and bottom of the cube. The cradle is adapted to be slightly rotated by means of arm 39 attached to stub shaft 38 which is tapped out to receive thecapstan screw 40 operatin between stops 41', 41.

y he object of providing this swinging adjustment of the mirror is to enable any error in manufacture to be corrected so that the mirror can be set finally exactly as In place of ailvering the mirror in stripe late 32,

' the receptacle having substantialltg the Ime REEL or geometric desi s it may be partially slvered so as to re ect a portion of the light and transmit a portion, or platinum or any other suitable material may be used for the purpose. The silver or other material on 10 either face may be protected from the action of the fluid used by coating with a protective transparent substance of muchthe same index of refraction, such as Canada balsem, Celluloid, or other substance, de- 16 pending largely on the refractive index of the glass used in the splitting mirror.

It is to be understood that the invention is not limited to the construction herein specifically illustrated and described, but can be embodied in other forms without de- .parture 'fromits spirit.

at I c is 1. A light splittin device com rising' a receptacle construe with a pluli'ality of 85 glass sides, one or more partly transparent glass mirrors mounted in the recepta e, and` a suitable Huid in the receptacle substantially the Same index 0f refraction Il the glass of said mirror or mirrors.

2. A light splittin device comprising a receptacle constructs with a plurality of glass sides, one or more mirrors having remg reflecting and transmitting arts mounted in the receptacle and a liqui in the laid receptacle of approximately the same index of refraction as the said glass mirrors.

3. A light splittin device comp a receptacle construe with a plurality of glass sides, one or more mirrors ha re- 100 fiecting and transinittin parts moun in the receptacle at an ang e of forty ve degrecs with the respective side through whidi it is adapted to project an image, and a luitable fluid in the receptacle having subetan- 108 tially the same index of refraction as the glass of said mirror or mirrors.

4. Alight splittin device comprising a receptacle constru with a plurality of glass sides, one or more ed in the receptacle apted to reect o portion of the light thun and transmit a portion, and a suitable liquid in the rece tac e having substantially um. index o refraction as the glass o said mir- IM mi 'iiim r 't d ig it in evica compri. a receptacle coiiiitruc with a pluraliof A' glass sides, one or more glass mirrors momit ed in the receptacle, one surface ofthe mirrors being partly coated with a highly r.eilective substance, and a suitable liqu d ln the same index of refraction aa gill of said or liitrrora.d

6. i t i tin evce comprising' a receptacleg conssptructe with a pluralty of glass sides, one or more glass mirrors mounted in the said receptace, the mirmrahavo one of their surfaces coatedinspota vwith Il. i

lass inirrora mountlil fiJiU//w wf 4/7 /5 JL) .4 j. DATE/naci EuPLoYEss No. DAT: ron/s DAT: ru. ciment' REEL onlwron L www i- 3 silver, and u. suitable liquid in the said receptacle having substantially the same index of refraction as the glass of said mirror or mirrors.

7. A light splittin device comprising a. receptacle construe with a plurality of glass sides, one or more lass mirrors mounted in the said receptac e, a suitable liquid in the receptacle having substantially the sume index of refraction as the glass eomposing the said mirror or mirrors, the mirrors lmvinf.r one of their surfaces coated in spots with silver and protected by a coating of some substance of about the same index of refraction as the glass mirrors and insol uble in the liquid used in the receptacle.

8. A light splittin device comprising n. receptacle constructe with two glass lates opposite each other, a third glass si e between the two said sides, a partly reflecting mirror in the said receptuclemounted at an Y angle of forty five degrees with the said third side, and a suitable liquid in the recvntacle having substantially the same index nI refraction as the glass of mid mirror or mirrors.

'receptacle construe 9. A light splittin device comprising a with two glass plates on opposite sides, two other glass plates between the said plates, referably on op site sides and stag ered) in relation to each other, two semire ecting mirrors mounted 1n the receptacle, each at an angle of fortymit of the expansion and contraction o the li uid in the rece ticle. r n testimony w ereof I hereunto ax my signature.

PEncY nlnnnws'rm." 

